Re: Merge replication or manual one?

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From: Darren Shaffer (darren_shaffer_at_nospam.com)
Date: 10/08/04 

Date: Fri, 8 Oct 2004 09:12:57 -0600

Merge is significantly more bandwidth intensive than RDA on GPRS.

If you use RDA, be aware of this scenario:
1. Device A pulls Table 1
2. Device B pulls Table 1
3. Device A changes row
4. Device B changes same row
5. Device A synchs to server
6. Device B synchs to server
Value on server is whatever Device B changed the row to. Device B never got
Device A's update. Device A doesn't have the latest update.

You don't have to create the GUID in your C# or VB.NET Code on device - let
the database do it for you in your insert statement using the newid()
function of SQL CE.

-Darren

"Freestyler" <freestyler@gazeta.pl> wrote in message
news:ck694h$hnc$1@inews.gazeta.pl...
> Thanks Darren
>
>> Moving to a WWAN (GPRS)
>> scenario, I'd eliminate merge based on my experience trying it for all of
>> Frontier Airlines
>> baggage handlers and then having to switch to RDA due to the bandwidth
>> required
>> by merge.
>
> Does it mean that there are great amount of data which slowes the
> replication
> and increases the cost of it ? (GPRS unfortunately is my must)
>
>
>> Beyond that, remember that RDA uses optimistic concurrency, so it is
>> possible
>> for changes from device B to overwrite changes from device A on the
>> server.
>
> Can not I set that Server is always "wiser" ?
> Do you know a site, where can I read some really good stuff about RDA?
>
>> One tip:
>> make everything you need to be unqiue across the system a GUID, it will
>> save you
>> headaches later.
>
> Guid is pretty big, and creating Guid in PPC is not that easy (fast).
> It's the easiest solution but is it the best?
>
> Cheers,
> Freestyler
>
>

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